I bought a Framus Cobra about four months ago with the matching straight cab. I love it, it's amazing, can do everything I could pretty much ever want an amp to do, but I think I might have damaged it. I have never fully understood the ohm system with speaker load vs amp output. I have tried hooking it up a couple different ways, and with using both the Framus cab and my Marshall 1960A cab. In my experimenting, I believe I might have slightly damaged my power transformer, output probably, because I don't think I have as much volume and headroom as I did before, I find myself having to push the amp incredibly hard to be heard in the band where I didn't before. And I have put all brand new tubes in with the same results. So, I have a couple questions. If my PT is damaged, should I send it to Framus or buy a tranny from them and get it shipped here and get my local tech to install it? And, can someone please explain the ohm system to me, as I believe I have been led astray. In the Cobra manual, it says if you have the amp on 4ohms (which is the most powerful setting, right?), you should hook up one 4ohm cab or 2x8ohm cabs. Now a question about the cab. I don't have and can't find a manual for either cab I own, but it appears on the framus that in mono it operates at 8ohms and 16ohms in stereo. Does the ohm capability of the cab change when you switch from stereo to mono, or not? To get the loudest ouput, should I use one speaker cable and run it in mono or two in stereo? Can the cab run in stereo at 8ohms AND 16ohms? I am really confused here and if someone could point me in the right direction here it would be much appreciated.
Framus Cobra Help NEEDED!
- Thread starter PurgeBand
- Start date
This has been mentioned several times before. IT WILL ONLY RUN STEREO WITH TWO AMPS....NOT TWO CABLES..(not yelling...just making sure people see it 
)
4 ohms is not really "most powerful". But with the framus I would suggest you run it at 8 ohms and use one cable. That is all there is to it.
As for the damage...I would have the local tech check to see if it is in fact damaged. Then contact framus and ask them what would be most efficient. If you have been running it at 4 ohms or 16 with two cables...the output transformer is most likely on its way out.
)4 ohms is not really "most powerful". But with the framus I would suggest you run it at 8 ohms and use one cable. That is all there is to it.
As for the damage...I would have the local tech check to see if it is in fact damaged. Then contact framus and ask them what would be most efficient. If you have been running it at 4 ohms or 16 with two cables...the output transformer is most likely on its way out.
If you have a cab and only one head, run the cab in mono, if you have a Marshall cab in mono the impedence is 16 Ohm, you must set the cobra at 16 Ohm and use only one output in this case. If you would set your cab stereo, the impedence is 8 Ohm...in this case you is like you have 2 cabinet of 8 Ohms, you must set the impedance of the cobra at 4 ohm and collegate the cab with 2 wire, but this operation is weird, becouse if you would have a stereo effect is better to have 2 heads.
I suggest you to go in mono, set the cab to mono, set the same impedence for the cab and cobra...and wire the cab with only one cable.
Are you using power cable or signal cable to connect the cobra in the cab?????
I suggest you to go in mono, set the cab to mono, set the same impedence for the cab and cobra...and wire the cab with only one cable.
Are you using power cable or signal cable to connect the cobra in the cab?????
I am assuming he has a cobra cab...in which case...set the head at 8 ohms and the cab at mono.
Hopefully he is using a speaker cable...
Hopefully he is using a speaker cable...
Yeah I am using a Cobra slant cab, and am using Planet Wave speaker cable. And I definitely did run it with the amp at 4ohms and using two speaker cables for a while, with the cab set on stereo. I also had it running at 4ohms w/ one speaker cable going to the cobra cab which was set to mono (8ohms) and the other going to the marshall, which was set to stereo, which is 8ohms also. I figured that would be alright for the cab, running it in stereo but only using half of it, that's the only way I could run it at 8ohms, and if you use 2cabs at 4ohms the manual says the cabs should be 8ohms each. Is there a formula for figuring out speaker load vs amp load? Anyway, I will try running it at 8ohms on the amp and the cab in mono with only one cable. So, my output tranny is probably half fried right? Which seems right, I have been pushing it extremely hard to be heard. But maybe I just had it hooked up wrong. I will try this setup from now on, but will probably have to get the OT replaced. Will probably cost about $1000 in total, right? Oh well, this amp is worth it, and I will NEVER hook it up wrong again. Thanks for the quick help by the way, much appreciated
